Reptiles and Amphibians of Illinois. 811 



Orotalus, Linn. 



Linnauis, Ace. Mas. Adolph. Frid., 1754, p. 39. 

 lid. and Gir., Cat. N. A. Kept, Ft. I., 1853. p. 1. 



Head deficient iu cephalic plates, the frontal and parietals 

 being absent and their place being occupied by small scales 

 like those on the body. Pit between the eye and nostril large. 

 Fangs and poison glands well developed. Supralabials sep- 

 arated from the orbit by three or more series of small plates. 

 Dorsal scales in from twenty-one to thirty-one rows, carinated. 

 Subcaudals entire or with one or two posterior divided. Rattle 

 present. Body moderately stout. Tail short. 



Crotalus horrid us, Linn. Timber Rattlesnake. 



Crotalus liorridus, Linn., Syst. Nat., ed. 10, 1758, 1., p. 214. 



Crotalus ditrlssufi, Holbr. N. A. Herp., 1842, III., p. 9, pi. 1. — De 

 Kay, Nat. Hist. N. Y., I., Zool. III., Kept, and Amph. 1842, p. 

 55, pi, 9, As. 19.— Kenn. Trans. 111. State Agr. Soc, 1853-54, 

 I., p. 592.— Bd. and Gir., Cat. N. A. Kept, Pt. I., 1853, p. 1. 



(Utudisona horrida. Cope, Proc. Acad. Nat. Sci. Phila., 1866, p. 309. 



Crotalus horridus, Davis & Rice, Bull. Ill State Lab. Nat. Hist., 

 I., No. 5, 1883, p. 27 ; Bull. Chicago Acad. Sci,, 1883.— S. Gar- 

 man, Mem. Mus. Comp. Zool., 1883, pp. 115, 174, pi. 9, fig. 1. 



Large, reaching a length of six feet. Body moderately short. 

 Neck contracted abruptly behind the head. Tail short, com- 

 pressed, not tapering. Rostral plate small, narrowed above. 

 Two nasals, the anterior larger. Two or more loreals. Two 

 anteorbitals, the superior larger, the inferior smaller and form- 

 ing the superior margin of the pit. About five postorbitals and 

 suborbitals, the latter separated from the supralabials by two 

 rows of scales. Supralabials fourteen, first and fifth (fourth in 

 some examples) largest. Fifteen infralabials. A pair of large 

 elongate submentals. Dorsal scales carinate, excepting the 

 outer rows, which are smooth or obsoleteiy carinate in front, 

 in from twenty-three to twenty-five rows. Ventrals 165. Sub- 

 caudals 28, the first and last paired. 



Color above brownish yellow to almost black, posteriorly 



with transverse zigzag bands of chestnut-brown, edged with 



black and bordered outside the black with yellow, anteriorly 



with three series of brown spots bordered in the same manner. 



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